ABSTRACT Affective disorders (ADs, i.e., depression and anxiety disorders), are the most common mental health conditions in the US. The prevalence of smoking among people with ADs is twice that of the general population. Smokers with ADs make as many attempts to quit smoking as those without ADs, but are more likely to relapse during quit attempts. As a result, people with ADs suffer from disproportionately-high rates of tobacco-related disease and death. In July 2017, the Food and Drug Administration (FDA) announced a comprehensive plan for regulating tobacco and nicotine products. A cornerstone of this plan is to reduce the nicotine content of cigarettes to a minimally-addictive level, in order to reduce tobacco dependence in the US. The parent project upon which this Predoctoral Fellowship to Promote Diversity in Health-Related Research (F31 - Diversity) application will build is a randomized clinical trial that will examine whether very low nicotine content cigarettes (VLNCCs) reduce smoking rates in smokers with ADs, and whether providing e-cigarettes enhances this effect. Smokers with ADs will be randomized to one of the following conditions for 16 weeks: (1) normal nicotine content research cigarettes (NNCCs) only, (2) VLNCCs only, (3) VLNCCs + tobacco-flavored e-cigarettes, or (4) VLNCCs + preferred-flavor e-cigarettes. Based on previous research, we expect that participants randomized to VLNCCs with or without e-cigarettes will partially but not fully substitute these study products for their usual cigarettes. This F31 will add a single session at the end of the parent grant for participants who had access to VLNCCs, e-cigarettes, and usual-brand cigarettes (i.e., those in conditions 3 and 4). The candidate will (1) investigate temporal and social-environmental contexts, relative risk perceptions, and subjective experiences of VLNCC, e-cigarette and usual brand cigarette use among individuals with ADs, (2) use a behavioral economics cross-price elasticity task to compare the relative reinforcing effects of VLNCCs, e-cigarettes and usual-brand cigarettes among individuals with ADs, and (3) investigate participants? opinions concerning a reduced-nicotine standard for cigarettes, whether and how they might circumvent such regulation, and whether the availability of e-cigarettes would affect the likelihood of their complying with this regulation. The proposed research will help us to understand factors contributing to VLNCC, e-cigarette and usual brand cigarette use in smokers with ADs. In turn, this knowledge may help regulators to maximize the effectiveness of a reduced-nicotine standard for cigarettes.